In whom (en wi). This locative form can refer to musthriou or to Cristou. It really makes no difference in sense since Christ is the mystery of God. All the treasures of wisdom and knowledge (pante oi qhsauroi th sopia kai gnwsew). See on Matthew 2:11 ; Matthew 6:19-21 for this old word, our thesaurus, for coffer, storehouse, treasure. Paul confronts these pretentious intellectuals (Gnostics) with the bold claim that Christ sums up all wisdom and knowledge. These treasures are hidden (apokrupoi, old adjective from apokruptw, to hide away, Mark 4:22 ) whether the Gnostics have discovered them or not. They are there (in Christ) as every believer knows by fresh and repeated discovery.